Taking a different approach to a creating a variable color temperature on-camera LED fixture,
Acebil's UC-600ALED CAMLIGHT incorporates dual 7W LEDs, one tungsten and one daylight balanced. Each light features its own dimmer mounted on the back of the unit, letting you individually control the light output of each LED to produce an aggregate beam with a color temperature between 3200 and 5600K.
The fixture mounts via your camera's accessory shoe and enables you to adjust its height and angle. The built-in aspherical optics provide a uniform beam, and the included 70 and 90° lenses allow you to adjust the beam spread. An included 7.9' D-Tap cable allows powering the light from batteries with a D-Tap output (batteries not included).